I'm still learning about Illustrator, but...

I took an old image of my buddy Mike, done up as Richard III, and ran it through Adobe Illustrator. My original intent was to convert the color raster (pixellated) image into a color vector file, with smooth edges and scalability (shrink or blow up while retaining perfect smoothness). I'm not at that point yet, but I've discovered Illustrator's "image trace" feature, which allowed me to convert the color raster graphic into a black-and-white vector graphic that I kinda like. There was something off about one of the eyes, though, and I've been trying to learn how to alter the vector image, so far without success. So what I did, as you'll see below, is to port the image over from Illustrator to Photoshop, which I'm very familiar with. Unfortunately, in Photoshop, the image had to be made raster again. I kept it high-res and high-dpi, though, and I was able to repair the eye problem. I like the new image, even if it's back to being raster. I'm still working on the original Illustrator document, so I hope to have the original as a color vector graphic soon. I saved the Photoshop doc as both a 600-dpi file and as a 72-dpi file, the latter of which is displayed below.

The original, original size, 200 pixels wide, 72 dpi:

The real original was smaller than 200 pixels wide, hence the fuzziness.

The black-and-white file, 72 dpi, 600 pixels wide:

While part of me wants the original color back, part of me likes what Illustrator did through that "image trace" function. I can re-add color in Photoshop, but the real point of the exercise is to do it in Illustrator.

Pedantic note: dpi and resolution do not mean the same thing. They're related concepts, but not identical. Dpi refers to dots per inch, i.e., how tiny the pixels are. At 300 dpi, you can make some very smooth images, but you're using a lot of memory to do so. At 600 dpi, you're halving the pixel size in two dimensions and therefore doubling the number of pixels along each axis (x and y), which means you're now using about four times the memory for your picture. Resolution, meanwhile, refers to the overall crispness and smoothness of your picture—more precisely, the total number of pixels needed to make your picture. You can conceivably make an image with a very low dpi that is still high-resolution. Imagine you're re-creating a photograph on a football field using thousands of colored balloons. If you fly up in a hot-air balloon a few hundred feet above the football field and look down, you'll see a crisp, high-resolution image. But the balloons, being so huge, are low-dpi, more like inches-per-dot than dots-per-inch. See how that works? So don't get caught using resolution and dpi interchangeably. They're distinct concepts.